This invention relates to conveyor apparatus. More particularly, the invention concerns a conveyor apparatus of the powered roller type in which the rollers are individually driven.
Conveyors are typically used to move objects along different paths, often negotiating turns between feeding and removal stations. Continuous belts have been used in some applications, while other conveyors use rotatably mounted rollers. These roller conveyors may use free-wheeling rollers which depend upon the force of gravity acting on the objects to move the objects down the conveyor line. Others use rollers which are positively driven by a motor. A conveyor apparatus having positively driven rollers can be susceptible to damaging the object or rollers when the object being conveyed becomes lodged between adjacent rollers. Thus, the slip drive or slippable rollers have been used in the industry to minimize this risk of damage. Devices of this type are described in the patent to Shuttleworth, et al, U.S. Pat. No. 3,951,255, assigned to the assignee of the present invention. Other "slippable" roller devices are shown in patents to Fleischauer, U.S. Pat. No. 3,961,700, Rae, U.S. Pat. No. 4,325,474, Allmacher, Jr., U.S. Pat. No. 4,401,208, and Musser, U.S. Pat. No. 3,369,646.
Each of these prior devices have various designs and criteria. For instance, some of these devices require relatively larger roller diameters, and are therefore not readily adapted for small conveyor apparatus. Others of these devices incorporate complicated driving structures that are not readily disassembled for repair and replacement. The Fleischauer and Musser devices disclose different designs for conveyor apparatus adapted for negotiating turns. For instance, the Fleischauer device is not readily usable for sharp turning radiuses because elongated shafts using U-joint interconnections are employed. Likewise, the Musser device requires a rotating table which would tend to restrict the sharpness of the turning angle for which that device is capable. In addition, the roller spacing in both Musser and Fleischauer is often too large to permit conveying relatively small objects along the apparatus.
In view of prior art devices, there is a need in the industry for a conveyor apparatus that provides for limited torque driven rollers having the capability for negotiating sharp turning radii and for use in relatively small conveyor applications.